An extended-wavelength exoplanet spectral model based on MODTRAN® 5

We overview a recently developed planetary radiative transfer (RT) model, PLANETS (PLANETary Spectroscopy), which is based on the MODTRAN^®5 band model RT algorithms. The basic features and RT algorithms are described and an application of PLANETS to a variety of observed Neptune spectra, spanning a broad spectral region, ultraviolet through far infrared, is highlighted. We also apply PLANETS to analysis of the recently reported observation of the thermal infrared emission spectrum of the exoplanet HR 8799c. We attribute the observed spectral features to CH₄ transmission and emission lines, located to the blue and red of the 4.3 μm CO₂ band edge, respectively.